1. Technical Field
The present invention is related generally to recombinant DNA. More particularly, the present invention is related to a recombinant cDNA clone encoding high affinity (about 10.sup.-8 to 10.sup.-10 Kd) cell surface receptors for laminin.
2. State of the Art
Laminin is a major glycoprotein component of basement membranes and mediates the attachment of both epithelial and neoplastic cells to the basement membrane. The basement membrane is a ubiquitous, specialized type of extracellular matrix separating organ parenchymal cells from interstitial collagenous stroma. Interaction of cells with this matrix is an important aspect of both normal and neoplastic cellular processes. Normal cells appear to require an extracellular matrix for survival, proliferation, and differentiation, while migratory cells, both normal and neoplastic, must traverse the basement membrane in moving from one tissue to another. In particular, metastatic cancer cells arising in squamous or glandular epithelium must traverse the basement membrane in moving from one tissue to another. In particular, metastatic cancer cells arising in squamous or glandular epithelium must traverse the basement membrane to enter the circulatory and lymphatic systems (intravasation); the circulating neoplastic cells are typically arrested in the capillary beds of an organ, invade the blood vessel walls, and penetrate the basement membrane to extravascular tissue (extravasation), where a secondary neoplasm is then established. Laminin receptor, by mediating the attachment of both epithelial and neoplastic cells to the basement membrane, plays a critical role in controlling, inter alia, the metastatic process. U.S. Pat. No. 4,565,789 describes the isolation and characterization of certain aspects of laminin receptor. But a cloned DNA sequence for encoding cell surface receptor for laminin has not heretofore been known.